I would say compression or the absence of heat because heating a liquid makes it a gas<span />
Answer:
Fe(CN)₂, FeCO₃, Pb(CN)₄, Pb(CO₃)₂
Explanation:
Cations (positively charged ions) can only form ionic bonds with anions (negatively charged ions). However, you can't just simply put one cation and one anion together to form a compound. Each compound needs to been neutral, or have an overall charge of 0. When cations and anions do not have charges that perfectly cancel, you need to modify the amount of each ion in the compound.
1.) Fe(CN)₂
-----> Fe²⁺ and CN⁻
-----> +2 + (-1) + (-1) = 0
2.) FeCO₃
-----> Fe²⁺ and CO₃²⁻
-----> +2 + (-2) = 0
3.) Pb(CN)₄
-----> Pb⁴⁺ and CN⁻
-----> +4 + (-1) + (-1) + (-1) + (-1) = 0
4.) Pb(CO₃)₂
-----> Pb⁴⁺ and CO₃²⁻
-----> +4 +(-2) + (-2) = 0
I believe this is a double replacement. As you can see none of the chemical symbols are missing, there just "replaced".
Ggggggggggggggggggggggggggggggggggggggg
I believe that the answer is D.
I hope this helps. :)
